|Publication number||US4747671 A|
|Application number||US 06/931,082|
|Publication date||31 May 1988|
|Filing date||17 Nov 1986|
|Priority date||19 Nov 1985|
|Also published as||DE3689788D1, DE3689788T2, EP0228557A2, EP0228557A3, EP0228557B1|
|Publication number||06931082, 931082, US 4747671 A, US 4747671A, US-A-4747671, US4747671 A, US4747671A|
|Inventors||Tohru Takahashi, Hiroshi Inoue, Yoshiyuki Osada, Yutaka Inaba, Junichiro Kanbe|
|Original Assignee||Canon Kabushiki Kaisha|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (6), Referenced by (64), Classifications (20), Legal Events (5)|
|External Links: USPTO, USPTO Assignment, Espacenet|
r.sub.1 C.sub.t <r.sub.2 C.sub.e
The present invention relates to an optical modulation device for a display panel and a driving method therefor, particularly an optical modulation device adapted to gradational or tonal display using a liquid crystal material, especially, a ferroelectric liquid crystal, and a driving method therefor.
In the conventional liquid crystal television panel of the active matrix driving system, thin film transistors (TFTs) are arranged in matrix corresponding to respective pixels. When a gate-on pulse is applied to a TFT to turn on the source-drain channel, a picture image signal is applied to the source and stored in a capacitor. A liquid crystal (e.g., TN (twisted nematic) liquid crystal) is driven by the stored image signal and a gradational display is effected by voltage modulation of pixels.
However, a television display panel of the active matrix driving system using a TN liquid crystal is a complicated TFT structure requiring a large number of production steps accompanied with a high production cost. Morever, there is a further problem that it is difficult to provide a large area of semiconductor film (e.g., of polysilicon, amorphous silicon) constituting TFTs.
On the other hand, a display panel of a passive matrix driving type using a TN liquid crystal has been known as one of a low production cost. However, in this type of liquid crystal display panel, when the number (N) of scanning lines is increased, a time period (duty factor) during which one selected point is subjected to an effective electric field during the time when one frame is scanned is decreased at a ratio of 1/N, whereby crosstalk occurs and a quality picture with high contrast cannot be obtained. Furthermore, as the duty factor is decreased, it is difficult to control gradation of respective pixels by means of voltage modulation so that this type of display is not adapted for a display panel of a high pixel or wiring density, particularly one for a liquid crystal television panel.
A principal object of the present invention is to solve the above problems.
A more specific object of the present invention is to provide an optical modulation device constituting a display panel of a high pixel density over a wide area and particularly suitable for a gradational display, and a driving method therefor.
More specifically, the present invention provides an optical modulation device, comprising: a first substrate having thereon a signal transmission electrode connected to a signal source and a first electrode having a delay function connected to the transmission electrode, a second substrate having thereon a second electrode disposed opposite to said first electrode, and an optical modulation material disposed between the first and second electrodes.
The present invention also provides a display system, particularly a gradational display system, using the above optical modulation device and utilizing the delay function.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention in conjunction with the accompanying drawings.
FIGS. 1 and 2 are schematic perspective views illustrating the operation principle of a ferroelectric liquid crystal device used in the present invention;
FIG. 3 is a partial perspective view of a substrate having a transmission electrode and a display electrode used in the present invention;
FIG. 4 is a schematic sectional view of an optical modulation device according to the present invention;
FIG. 5 shows an example of a scanning signal;
FIGS. 6A-6F show examples of gradation signals used in the present invention, and FIGS. 7A-7F show schematic sketches showing bright-to-dark gradational states of a pixel obtained correspondingly;
FIG. 8 is a schematic plan view showing a matrix electrode arrangement used in the present invention; and
FIGS. 9A-9E are schematic sketches showing another set of bright-to-dark gradational states.
As an optical modulation material used in the driving method according to the present invention, a material which shows a first optically stable state (e.g., assumed to form a "bright" state) and a second optically stable state (e.g., assumed to form a "dark" state) depending on an electric field applied thereto, i.e., one showing at least two stable states in response to an electric field, particularly a liquid crystal showing such a property, may be used.
Preferable ferroelectric liquid crystals showing at least two stable states which can be used in the driving method according to the present invention are chiral smectic liquid crystals having ferroelectricity, among which liquid crystals showing chiral smectic C phase (SmC*), H phase (SmH*), I phase (SmI *), F phase (SmF*) or G phase (SmG*) are suitable. These ferroelectric liquid crystals are described in, e.g., "LE JOURNAL DE PHYSIQUE LETTERS" 36 (L-69), 1975 "Ferroelectric Liquid Crystals"; "Applied Physics Letters" 36 (11) 1980, "Submicro Second Bistable Electrooptic Switching in Liquid Crystals", "Kotai Butsuri (Solid State Physics)" 16 (141), 1981 "Liquid Crystal", etc. Ferroelectric liquid crystals disclosed in these publications may be used in the present invention.
More particularly, examples of ferroelectric liquid crystal compound usable in the method according to the present invention include decyloxybenzylidene-p'-amino-2-methylbutyl cinnamate (DOBAMBC), hexyloxybenzylidene-p'-amino-2-chloropropyl cinnamate (HOBACPC), 4-o-(2-methyl)-butylresorcylidene-4'-octylaniline (MBRA 8), etc.
When a device is constituted using these materials, the device may be supported with a block of copper, etc., in which a heater is embedded in order to realize a temperature condition where the liquid crystal compounds assume an SmC*, SmH*, SmI*, SmF* or SmG* phase.
Referring to FIG. 1, there is schematically shown an example of a ferroelectric liquid crystal cell for explanation of the operation thereof. Reference numerals 11a and 11b denote base plates (glass plates) on which a transparent electrode of, e.g., In2 O3, SnO2, ITO (Indium-Tin-Oxide), etc., is disposed, respectively. A liquid crystal of, e.g., an SmC*-phase in which liquid crystal molecular layers 12 are oriented perpendicular to surfaces of the glass plates is hermetically disposed therebetween. Full lines 13 show liquid crystal molecules. Each liquid crystal molecule 13 has a dipole moment (P.sub.⊥) 14 in a direction perpendicular to the axis thereof. When a voltage higher than a threshold level is applied between electrodes formed on the base plates 11a and 11b, a helical structure of the liquid crystal molecule 13 is unwound or released to change the alignment direction of respective liquid crystal molecules 13 so that the dipole moments (P.sub.⊥) 14 are all directed in the direction of the electric field. The liquid crystal molecules 13 have an elongated shape and show refractive anisotropy between the long axis and the short axis thereof. Accordingly, it is easily understood that when, for instance, polarizers arranged in a cross nicol relationship, i.e., with their polarizing directions crossing each other, are disposed on the upper and the lower surfaces of the glass plates, the liquid crystal cell thus arranged functions as a liquid crystal optical modulation device, of which optical characteristics vary depending upon the polarity of an applied voltage. Further, when the thickness of the liquid crystal cell is sufficiently thin (e.g., 1μ), the helical structure of the liquid crystal molecules is unwound even in the absence of an electric field whereby the dipole moment assumes either of the two states, i.e., Pa in an upper direction 23a or Pb in a lower direction 24a as shown in FIG. 2. When electric field Ea or Eb higher than a certain threshold level and different from each other in polarity as shown in FIG. 2 is applied to a cell having the above-mentioned characteristics, the dipole moment is directed either in the upper direction 24a or in the lower direction 24b depending on the vector of the electric field Ea or Eb. In correspondence with this, the liquid crystal molecules are oriented in either of a first stable state 23a (bright state) and a second stable state 23b (dark state).
When the above-mentioned ferroelectric liquid crystal is used as an optical modulation element, it is possible to obtain two advantages: (1) the response speed is quite fast and (2) the orientation of the liquid crystal shows bistability. The second advantage will be further explained, e.g., with reference to FIG. 2. When the electric field Ea is applied to the liquid crystal molecules, they are oriented in the first stable state 23a. This state is stably retained even if the electric field is removed. On the other hand, when the electric field Eb of which direction is opposite to that of the electric field Ea is applied thereto, the liquid crystal molecules are oriented to the second stable state 23b, whereby the directions of molecules are changed. This state is also stably retained even if the electric field is removed. Further, as long as the magnitude of the electric field Ea or Eb being applied is not above a threshold value, the liquid crystal molecules are placed in the respective orientation states. In order to effectively realize high response speed and bistability, it is preferable that the thickness of the cell is as thin as possible and generally 0.5 to 20μ, particularly 1 to 5μ. A liquid crystal-electrooptical device having a matrix electrode structure in which the ferroelectric liquid crystal of this kind is used is proposed, e.g., in the specification of U.S. Pat. No. 4,367,924 by Clark and Lagerwall.
An embodiment of the display device according to the present invention will now be explained with reference to FIG. 3.
In FIG. 3, a glass substrate 31 has thereon an electrode 32 which has a delay function in the direction of an arrow 32a and constitutes one side of display electrode, and a transmission electrode 33. The display electrode 32 has a region A defining a pixel. Facing the display electrode 32, a counter electrode is disposed on the other substrate (not shown) at a region on the other substrate corresponding to region A. An optical modulation material is sandwiched between the display electrode and the counter electrode. The case where the resistivity of the counter electrode is sufficiently low is considered. The region A is assumed as one pixel which is square in shape. A signal which has been supplied through the transmission electrode 33 having a sufficiently low resistivity propagates through the electrode 32 in the direction of arrow 32a, and the propagation time is characterized by R×C, wherein R denotes the sheet resistivity of the electrode 32 (Ω/□) and C denotes a capacitance formed by the display electrode and the counter electrode at the region A (F).
According to a device using such a combination of a transmission electrode and a display electrode having a delay function, the following two advantages are obtained.
(1) An electric signal supplied to a terminal of the transmission electrode (or display electrode) propagates through the transmission electrode at a high velocity and then through the display electrode having a delay function. As a result, disuniformity of electrical signal along the longitudinal direction of the display electrode denoted by 32b in FIG. 3 is extremely minimized, whereby the voltage applied to an optical modulation device is uniformized along this direction.
(2) By utilizing a voltage distribution or gradient in the direction 32b on the display electrode, and by applying a gradational signal modulated with respect to voltage, pulse duration or pulse number as an input signal, a gradational display may be effected.
The above point (2) will be explained in detail with reference to an example.
Referring to FIG. 3, an about 100 Å-thick semitransparent Ge layer was formed by sputtering on a glass substrate 31. The sheet resistivity of the layer was 5×107 Ω/□. The layer was patterned to form a display electrode 32 as shown in FIG. 3. The width of the display electrode in the direction of 32a was made 230μ (while the width may be arbitrarily determined and generally suitably be in the range of 20μ to 500μ. Then, A1 was vapor-deposited under vacuum in a thickness of 1000 Å and again patterned to form a transmission electrode 33 as shown in FIG. 3. The A1 layer formed in the above described manner provided a low resistivity of about 0.4 Ω/□ and formed into a width of about 20μ. On the other hand, on the counter substrate, a transparent ITO (indium-tin-oxide) layer was formed as a counter electrode so as to cover the region A. The ITO layer showed a sheet resistivity of about 20 Ω/□.
On the two substrates prepared in the above described manner, an about 500 Å-thick polyvinyl alcohol layer was formed and subjected to a rubbing treatment.
Then, the two substrates were disposed to face each other and secured to each other with a controlled gap of about 1μ to form a cell, into which a ferroelectric liquid crystal composition consisting mainly of p-n-octyloxybenzoic acid-p'-(2-methylbutyloxy)phenyl-ester and p-n-nonyloxybenzoic acid-p'-(2-methylbutyloxy)phenyl-ester, was injected. The region A (as shown by A in FIG. 3) at which the display electrode and the counter electrode overlapped each other had a size of 230×230μ, and provided a capacitance of about 3 pF after the injection of the liquid crystal.
On both sides of the liquid crystal cell thus prepared, a pair of polarizers were disposed in the form of cross nicols, and the optical characteristics were observed.
FIG. 4 schematically illustrates a method of applying electric signals to a liquid crystal cell which includes a counter electrode 41, a counter substrate 42, and a liquid crystal layer 44 disposed therebetween, and FIGS. 5 and 6A-6F show examples of electric signals applied. FIG. 5 shows a waveform of SIGNAL(a) shown applied through a driver circuit 43 in FIG. 4 and FIGS. 6A-6F show waveforms of SIGNAL(b) applied through a driver circuit 44 in FIG. 4. The voltage waveform effectively applied to the liquid crystal layer varies depending on a distance from the transmission electrode.
Now, a pulse of -12 V, 200 μsec as SIGNAL(a) and a pulse of 8 V, 200 μsec as SIGNAL(b) were applied in phase with each other in advance. These pulses are referred to as erasure pulses. Then, the liquid crystal was switched or brought to the first stable state shown in FIG. 1 or FIG. 2, thereby to render the whole pixel A "bright" as the polarizers were arranged in that manner. At this state, various pulses as shown in FIGS. 6A-6F were applied respectively in phase with the pulse shown in FIG. 5, whereby the pixel A provided optical states as shown in FIGS. 7A-7F.
More specifically, for pulse durations of 30 μsec (corresponding to FIG. 6A) and 60 μsec (corr. to FIG. 6B), no change occurred from the bright state 72 (FIGS. 7A and 7B). For a pulse duration of 120 μsec (corr. to FIG. 6C), the portion of the liquid crystal close to the transmission electrode 33 was switched to the dark state 71 (FIG. 7C). Further, as the pulse duration was increased to 150 μsec (FIG. 6D) and 170 μsec (FIG. 6E), the region of the dark state 71 became wider (FIGS. 7D and 7E). Finally, when the pulse duration was 200 μsec (FIG. 6E), the whole pixel A was switched to the dark state (FIG. 7F). In this way, an image with gradation may be obtained.
In the above example, gradation signals applied were those having the same voltage and different pulse durations. Alternatively, gradation signals having the same pulse duration and different voltages or waveheights or intensities may also be used according to the principle of the present invention. The voltage values for this purpose may for example be selected at (A) -2 V, (B) -3 V, (C) -4 V, (D) -5 V, (E) -6 V and (F) -9 V, when the pulse duration is fixed, e.g., at 180 μsec. Further, it is also possible to effect a similar gradational display by selecting a particular pulse duration and modulating the number of pulses (or frequency) thereof.
By the way, a display with a large number of pixels with a simple matrix electrode structure may be formed in a manner as illustrated by FIG. 8. Thus, the matrix electrode structure comprises signal (display electrodes) corresponding to pixel electrodes 82 (I1, I2, I3, . . .); transmission electrodes 83 each disposed along the pixel electrodes and receiving gradation signals corresponding to image signals; scanning electrodes 84 corresponding to the counter electrodes; and auxiliary conductors for preventing delay of electric signals in a direction along the longitudinal direction of the scanning electrodes.
Hereinbelow, the present invention will be explained more specifically based on an embodiment as shown in FIG. 8.
Electrodes or conductors having the following dimensions or particulars were disposed.
Scanning electrodes 84:
length: 210 mm,
pitch: 250 μm,
width: 230 82 m,
material: ITO (sheet resistivity: 20 Ω/□).
Auxiliary conductors 85: A1 stripe
width: 20 μm×2,
thickness: 1000 Å (sheet resistivity: 0.4 Ω/□).
Signal (display) electrodes 82:
length: 298 mm,
pitch: 250 μm,
width: 230 μm,
material: Ge (germanium).
Transmission electrodes 83: A1 stripe
width: 20 μm×1,
thickness: 1000 Å (sheet resistivity: 0.4 Ω/□
The following pulses were applied:
Scanning pulse (line-by-line driving):
voltage: +12 V
duration: 200 μsec.
Gradation signal pulse:
voltage: -9 V to +9 V (5 gradation steps)
duration: 200 μsec.
The liquid crystal material used was a ferroelectric liquid crystal composition consisting mainly of p-n-octyloxybenzoic acid-p'-(2-methylbutyloxy)phenyl ester and p-n-nonyloxybenzoic acid-p'-(2-methylbutyloxy)phenyl ester and was used in a layer with a thickness of about 1 μm.
In the present invention, the transmission electrode may comprise a film of a metal such as gold, copper, silver or chromium instead of an aluminum film. It is generally preferred that the transmission electrode has a sheet resistivity (as measured according to ASTM D257 with respect to film having a sufficient area separately prepared under the same film forming conditions) of 102 Ω/□ or below. Further, the display electrode may be a film of a metalloid such as Ge, GeTe alloy, GeSe alloy etc., or a film of a metal oxide such as SnO2. The ratio of the sheet resistivity of the display electrode to that of the transmission electrode should preferably be larger than 1.5.
In the present invention, the resistivity of the pixel electrode and the resistivity of the transmission electrode are required to be set to appropriate values so as not to provide a fluctuation in voltage applied to the liquid crystal layer in the lengthwise direction of the pixel electrode but to provide an effective gradation effect in the transverse direction of the pixel electrode. The condition for this purpose is set forth as follows:
r.sub.1 C.sub.t <r.sub.2 Ce (1),
wherein r1 denotes the resistance of the transmission electrode as viewed from the signal source (Ω); Ct denotes the total capacitance corresponding to all the pixel electrodes connected to the transmission electrode (F); and r2 and Ce denote the resistance and the capacitance, respectively, of a pixel electrode corresponding to one pixel as viewed from the transmission electrode (Ω).
The respective values were confirmed with respect to the example based on FIG. 7 as follows:
r1 ≈0.4×(298×103)/20 ≈6×103 Ω
r2 ≈5×107 Ω
From the above, the following values were obtained:
r1 Ct ≈18 μsec, and
r2 Ce≈150 μsec.
Thus, condition (1) is satisfied.
In the above example, a gradational display was realized by using a sufficiently low resistivity of an electrode to which a scanning signal is applied and a high resistivity of a display electrode on a line to which an information signal is applied. However, by applying the principle of the present invention as it is, a similar gradational display effect as obtained in the example can be obtained by providing a delay function or effect to an electrode to which a scanning signal is applied and providing a sufficiently low resistivity to an electrode to which an information signal is applied. More specifically, the liquid crystal cell having the matrix structure used in the above example was driven by exchanging the roles of the scanning electrodes and signal electrodes, whereby very good gradational expression can also be attained.
FIGS. 9A-9E illustrate another embodiment of application with gradational display states obtained thereby. More specifically, in the embodiment, both the scanning electrodes and the signal electrodes are constituted to comprise combinations of transmission electrodes 33 (on signal electrode side) or 33a (on counter electrode side) and related electrodes connected to the transmission electrodes.
As described above, according to the present invention, the following effects are attained.
(1) An electric signal supplied to a terminal of a transmission electrode (or display electrode) propagates through the transmission electrode at a high velocity and then through the display electrode having a delay function. As a result, disuniformity of electrical signal along the longitudinal direction of the display electrode is extremely minimized, whereby the voltage applied to an optical modulation device is uniformized along this direction.
(2) By utilizing a voltage distribution or gradient on the display electrode, and by applying a gradational signal modulated with respect to voltage, pulse duration, or pulse number as an input signal, a gradational display may be effected.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US4326776 *||24 May 1979||27 Apr 1982||Kabushiki Kaisha Suwa Seikosha||Matrix electrode construction|
|US4335937 *||27 Oct 1978||22 Jun 1982||Sharp Kabushiki Kaisha||Electrode assembly of a liquid crystal display|
|US4384763 *||26 Aug 1980||24 May 1983||Rca Corporation||Double layer liquid crystal device for a dot matrix display|
|US4390244 *||23 Jul 1980||28 Jun 1983||Thomson-Csf||Liquid crystal visual display unit and telephone terminal incorporating such a unit|
|US4508429 *||13 Apr 1983||2 Apr 1985||Hitachi, Ltd.||Method for driving liquid crystal element employing ferroelectric liquid crystal|
|US4591886 *||9 Jul 1984||27 May 1986||Hitachi, Ltd.||Driving method and apparatus for optical printer with liquid-crystal switching element|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4796980 *||27 Mar 1987||10 Jan 1989||Canon Kabushiki Kaisha||Ferroelectric liquid crystal optical modulation device with regions within pixels to initiate nucleation and inversion|
|US4815823 *||26 Jan 1988||28 Mar 1989||Canon Kabushiki Kaisha||Electro-optical device with plural low resistive portions on each high resistive electrode|
|US4852978 *||23 Jun 1987||1 Aug 1989||Stc Plc||Liquid crystal cell utilizing a ferroelectric liquid crystal having a natural pitch length is no longer than the longest wavelength of visible light|
|US4906072 *||6 Oct 1987||6 Mar 1990||Canon Kabushiki Kaisha||Display apparatus and driving method for providing an uniform potential to the electrodes|
|US5007716 *||11 Jan 1989||16 Apr 1991||Canon Kabushiki Kaisha||Liquid crystal device|
|US5033822 *||10 Aug 1989||23 Jul 1991||Canon Kabushiki Kaisha||Liquid crystal apparatus with temperature compensation control circuit|
|US5111320 *||29 Nov 1990||5 May 1992||Xerox Corporation||Ferrolectric liquid crystal devices having improved operating properties by using an electronic mask|
|US5124816 *||20 Apr 1990||23 Jun 1992||Canon Kabushiki Kaisha||Method of disconnecting short-circuited part between upper and lower electrodes of liquid crystal display panel, and process of preparing liquid crystal display panel by using the same|
|US5124826 *||13 Dec 1990||23 Jun 1992||Canon Kabushiki Kaisha||Liquid crystal device|
|US5187601 *||17 Dec 1991||16 Feb 1993||Semiconductor Energy Laboratory Co., Ltd.||Method for making a high contrast liquid crystal display including laser scribing opaque and transparent conductive strips simultaneously|
|US5204659 *||3 Aug 1990||20 Apr 1993||Honeywell Inc.||Apparatus and method for providing a gray scale in liquid crystal flat panel displays|
|US5223963 *||12 Feb 1992||29 Jun 1993||Canon Kabushiki Kaisha||Chiral smectic liquid crystal device with different pretilt angles in pixel and non-pixel areas|
|US5227899 *||5 Sep 1991||13 Jul 1993||Sharp Kabushiki Kaisha||Liquid crystal display device with low resistance film separated from one of two adjacent electrodes by an insulating film|
|US5264954 *||19 Feb 1992||23 Nov 1993||Canon Kabushiki Kaisha||Liquid crystal device having a plural stripe-shaped ribs on one substrate for providing gradation display|
|US5293534 *||28 Jul 1992||8 Mar 1994||Canon Kabushiki Kaisha||Liquid crystal device|
|US5296870 *||28 Mar 1991||22 Mar 1994||U.S. Philips Corporation||Matrix display devices|
|US5321537 *||16 Mar 1993||14 Jun 1994||Canon Kabushiki Kaisha||Method for producing chiral smectic liquid crystal device including masking areas between electrodes, rubbing, removing mask, and rubbing again|
|US5379138 *||15 Feb 1994||3 Jan 1995||Canon Kabushiki Kaisha||Bi-stable liquid crystal device and driving method which allows for time variable threshold voltages|
|US5408246 *||18 Jul 1994||18 Apr 1995||Canon Kabushiki Kaisha||Electro-optical modulating apparatus and driving method thereof|
|US5436490 *||20 Oct 1992||25 Jul 1995||Rohm Co., Ltd.||Semiconductor device having ferroelectrics layer|
|US5446570 *||21 Apr 1994||29 Aug 1995||Canon Kabushiki Kaisha||Liquid crystal display with projecting portions on the electrodes|
|US5499130 *||5 Jun 1995||12 Mar 1996||Canon Kabushiki Kaisha||Method of making liquid crystal device having plural stripe-shaped ribs on one substrate|
|US5539553 *||30 Mar 1994||23 Jul 1996||Canon Kabushiki Kaisha||Liquid crystal device with an electrically neutral interface between the liquid crystal and orientation layer|
|US5541752 *||1 Aug 1994||30 Jul 1996||Canon Kabushiki Kaisha||Liquid crystal apparatus|
|US5552911 *||15 Oct 1993||3 Sep 1996||Canon Kabushiki Kaisha||Color liquid crystal display device having varying cell thickness and varying pixel areas|
|US5608420 *||22 Mar 1994||4 Mar 1997||Canon Kabushiki Kaisha||Liquid crystal display apparatus|
|US5612802 *||17 Jan 1995||18 Mar 1997||Canon Kabushiki Kaisha||Chiral smectic liquid crystal device having alignment film over electrodes being different and having different pretilt from alignment film between electrodes|
|US5657103 *||7 Jun 1995||12 Aug 1997||Canon Kabushiki Kaisha||Liquid crystal device|
|US5729314 *||4 Apr 1996||17 Mar 1998||Canon Kabushiki Kaisha||Liquid crystal device having orientation layer with neutral molecules absorbed at liquid crystal interface|
|US5798743 *||7 Jun 1995||25 Aug 1998||Silicon Light Machines||Clear-behind matrix addressing for display systems|
|US5815130 *||1 Jun 1995||29 Sep 1998||Canon Kabushiki Kaisha||Chiral smectic liquid crystal display and method of selectively driving the scanning and data electrodes|
|US5815131 *||4 Sep 1997||29 Sep 1998||Canon Kabushiki Kaisha||Liquid crystal apparatus|
|US5844536 *||6 Jun 1995||1 Dec 1998||Canon Kabushiki Kaisha||Display apparatus|
|US5856814 *||1 Aug 1996||5 Jan 1999||Canon Kk||Driving method for display apparatus|
|US5856815 *||16 Jul 1996||5 Jan 1999||Fujitsu Limited||Method of driving surface-stabilized ferroelectric liquid crystal display element for increasing the number of gray scales|
|US5982553 *||20 Mar 1997||9 Nov 1999||Silicon Light Machines||Display device incorporating one-dimensional grating light-valve array|
|US6037922 *||12 Jun 1996||14 Mar 2000||Canon Kabushiki Kaisha||Optical modulation or image display system|
|US6064404 *||5 Nov 1996||16 May 2000||Silicon Light Machines||Bandwidth and frame buffer size reduction in a digital pulse-width-modulated display system|
|US6081252 *||11 Jul 1997||27 Jun 2000||National Semiconductor Corporation||Dispersion-based technique for performing spacial dithering for a digital display system|
|US6088102 *||31 Oct 1997||11 Jul 2000||Silicon Light Machines||Display apparatus including grating light-valve array and interferometric optical system|
|US6101036||23 Jun 1998||8 Aug 2000||Silicon Light Machines||Embossed diffraction grating alone and in combination with changeable image display|
|US6130770 *||23 Jun 1998||10 Oct 2000||Silicon Light Machines||Electron gun activated grating light valve|
|US6133894 *||12 Dec 1997||17 Oct 2000||Canon Kabushiki Kaisha||Driving method for optical apparatus|
|US6175355||11 Jul 1997||16 Jan 2001||National Semiconductor Corporation||Dispersion-based technique for modulating pixels of a digital display panel|
|US6195137||13 Nov 1995||27 Feb 2001||Canon Kabushiki Kaisha||Liquid crystal apparatus|
|US6215579||24 Jun 1998||10 Apr 2001||Silicon Light Machines||Method and apparatus for modulating an incident light beam for forming a two-dimensional image|
|US6271808||5 Jun 1998||7 Aug 2001||Silicon Light Machines||Stereo head mounted display using a single display device|
|US6590558 *||19 Jun 2001||8 Jul 2003||Hewlett-Packard Company||Electro-optic displays|
|US6707591||15 Aug 2001||16 Mar 2004||Silicon Light Machines||Angled illumination for a single order light modulator based projection system|
|US6712480||27 Sep 2002||30 Mar 2004||Silicon Light Machines||Controlled curvature of stressed micro-structures|
|US6714337||28 Jun 2002||30 Mar 2004||Silicon Light Machines||Method and device for modulating a light beam and having an improved gamma response|
|US6728023||28 May 2002||27 Apr 2004||Silicon Light Machines||Optical device arrays with optimized image resolution|
|US6747781||2 Jul 2001||8 Jun 2004||Silicon Light Machines, Inc.||Method, apparatus, and diffuser for reducing laser speckle|
|US6764875||24 May 2001||20 Jul 2004||Silicon Light Machines||Method of and apparatus for sealing an hermetic lid to a semiconductor die|
|US6767751||28 May 2002||27 Jul 2004||Silicon Light Machines, Inc.||Integrated driver process flow|
|US6782205||15 Jan 2002||24 Aug 2004||Silicon Light Machines||Method and apparatus for dynamic equalization in wavelength division multiplexing|
|US6800238||15 Jan 2002||5 Oct 2004||Silicon Light Machines, Inc.||Method for domain patterning in low coercive field ferroelectrics|
|US6801354||20 Aug 2002||5 Oct 2004||Silicon Light Machines, Inc.||2-D diffraction grating for substantially eliminating polarization dependent losses|
|US6806997||28 Feb 2003||19 Oct 2004||Silicon Light Machines, Inc.||Patterned diffractive light modulator ribbon for PDL reduction|
|US6813059||28 Jun 2002||2 Nov 2004||Silicon Light Machines, Inc.||Reduced formation of asperities in contact micro-structures|
|US6822797||31 May 2002||23 Nov 2004||Silicon Light Machines, Inc.||Light modulator structure for producing high-contrast operation using zero-order light|
|US6829077||28 Feb 2003||7 Dec 2004||Silicon Light Machines, Inc.||Diffractive light modulator with dynamically rotatable diffraction plane|
|US6829092||15 Aug 2001||7 Dec 2004||Silicon Light Machines, Inc.||Blazed grating light valve|
|US6829258||26 Jun 2002||7 Dec 2004||Silicon Light Machines, Inc.||Rapidly tunable external cavity laser|
|U.S. Classification||349/85, 349/147, 359/900, 348/E03.015, 345/97, 349/37|
|International Classification||G02F1/137, G02F1/141, G02F1/133, H04N3/12, G09G3/36, G09G3/20|
|Cooperative Classification||Y10S359/90, H04N3/127, G09G3/2014, G09G3/3637, G09G3/207, G09G3/2011|
|European Classification||G09G3/36C6B4, H04N3/12L|
|17 Nov 1986||AS||Assignment|
Owner name: CANON KABUSHIKI KAISHA, 3-30-2 SHIMOMARUKO, OHTA-K
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:TAKAHASHI, TOHRU;INOUE, HIROSHI;OSADA, YOSHIYUKI;AND OTHERS;REEL/FRAME:004628/0819
Effective date: 19861110
|27 Dec 1988||CC||Certificate of correction|
|30 Sep 1991||FPAY||Fee payment|
Year of fee payment: 4
|22 Sep 1995||FPAY||Fee payment|
Year of fee payment: 8
|22 Nov 1999||FPAY||Fee payment|
Year of fee payment: 12